This is a strange book. David Cannadine, a distinguished historian of 19th-century Britain, has taken it upon himself to admonish the historical profession for setting up a series of unhelpful oppositions in its narratives of the past, emphasising division rather than collaboration, conflicting identities rather than a common humanity. He chides us for not writing about the boring bits in between, when people got on with each other; instead, he claims, we are always chasing after the newsworthy moments of the past, when people evidently did not.

To illustrate his point, Cannadine isolates six forms of identity in which historians have helped to cement unreal antagonisms: religion, nation, class, gender, race and civilisation. Instead of compartmentalising history by focusing on one form of identity at the expense of others, Cannadine insists – and who would question this? – that we have multiple and shifting identities. It is possible to be a woman, black, a worker, a Christian and British all at the same time. Yet this is so obvious that it scarcely needs to be stated. Cannadine’s fear is that historians impose on figures from the past – and, by implication, on those around us today – a single identity, seeing all workers, for example, as potentially class-conscious proletarians; or all Christians as bearers, through the ages, of anti-Semitic and anti-Islamic prejudices or hatreds; or all women as waiting to be liberated from a male-constructed universe.

The most problematic of these categories is civilisation. Here, too, Cannadine insists that historians have been responsible for taking an approach to the past (and the present) that has divided humanity into broad aggregations based on the idea of separate and identifiable civilisations, which, almost by definition, will be antagonistic and which, in the hands of generations of western writers, have been contrasted with the “barbarian”.

This last category, as Cannadine recognises, goes back as far, if not further, than the ancient Greeks, for whom the barbarian was other or alien. In the 19th century, historians contrasted the Greek and Roman heritage and its survival through the Renaissance and the Enlightenment with the “barbarous” societies of Africa and Asia and the peoples encountered in the New World.

In the 20th century, civilisation-counting became de rigueur, with Arnold Toynbee and Oswald Spengler its leading exponents. Samuel P Huntington’s 1996 book, The Clash of Civilisations, is, for Cannadine, the end point of this damaging effort to divide the history of humanity into stories of “us” against “them”. This effort lies, he suggests, at the root of the current struggle between “western” values and ways of life and the invisible threat of international terrorism.

Cannadine writes about all these things as engagingly and fluently as ever. He is no doubt right that some historians over the past century or so, when historical writing in the west has become professionalised and widely practised, have helped to create conflicts of identity that are overdrawn and at times pernicious. It is tempting to project current concerns and prejudices back on to the past, turning every woman in 19thcentury Europe into a victim of universal misogyny or every black man into a victim of white supremacism. Historians have played their part in the creation of national identities that are more imagined than real, as well as in fomenting national rivalries, inadvertently or otherwise.

The history of war is habitually written by the winners, so that “good-war” narratives gloss over the awful reality of all human conflict, especially when the enemy can be defined as barbarous. Not for nothing was the word “Hun” used to describe the Germans in two world wars (and historians certainly helped by hunting for German atrocities in order, implicitly rather than explicitly, to confirm the barbarous sobriquet).

Cannadine reserves his most powerful indictment for those 20th-century historians who, from a Marxist or sub-Marxist point of view, peddled Karl Marx’s view that all history is the history of class struggle and should be written as such. The arch-villains here are, predictably, Eric Hobsbawm and E P Thompson, though the net can be spread widely from the 1920s up to the 1970s, when postmodernism is said to have challenged “hegemonic” narratives of nation, class and elite. Historians who subscribed to the Marxist model (though not necessarily Marxists themselves) not only defined the past in class terms, from the Spartacus revolt of 73 BC to the triumph of Hitler in 1933, but helped to shape the questions that other historians were supposed to ask about the past – hence endless histories of trade union movements, co-operatives, labour relations and class identities, not to mention Cannadine’s work on the declining aristocracy.

In the 1960s, Marxism seemed a solid reference point for understanding the varieties of the past. Now, Cannadine tells us, Marxism is dead and buried, overcome by how class identity is in some ways the weakest of the collectivities imposed on history, unable to explain or to undermine the appeal of religion, nation or gender.

There are some obvious objections to make to Cannadine’s thesis. He has clearly not been paying attention to the direction in which historical writing in Britain and the United States has been moving over the past few decades. The subjects that now interest historians are to be found in everyday life – sex, fashion, food, even noise or dirt – and in the gaps between the old narratives and their battles, murders and commotion. Historical methodology is now rooted in an obsession with “transnational” pasts – just the kind of fluid intercourse between social groups, national units or civilisations that Cannadine argues has been neglected. Contacts, networks and translations are all the rage.

It is hard to think of any historian who still subscribes to the older verities, so much so that the word “class” (which was a historical concept, invented by Hegel years before Marx) is now regarded as a relic from a bygone age. A great deal of history today is written about historians and the way in which “public history”, as it is called, has been distorted by the values of an earlier generation of writers. Much of this work, including Cannadine’s book, which is based on his 2007 Trevelyan lectures at the University of Cambridge, aims to refine the crude categories that have been imposed on past societies in order to understand them better and to overcome enduring prejudices and assumptions about “the other”. Schoolchildren are now taught in history lessons to sniff out “bias”.

A more simple objection is that historians have often supplied a critical and dissenting voice and have countered crude stereotyping and popular prejudice. Although the current obsession in English schools with the Nazis is perhaps excessive, it is nevertheless a powerful vehicle for exposing all forms of racial prejudice and state oppression. It is precisely because history is an awkward and critical discipline that its capacity to influence how people think or have thought is much more limited than historians like to claim. The small cabals of historians invited to meet, say, Margaret Thatcher or George W Bush were ornamental, not essential. For much of the time, historians have contested realities that they did little to shape.

In his introduction, Cannadine does concede that his six categories are sustained by “pundits, politicians and the public” but he adds that “many engaged academics” (whatever that means) want to define the world in terms of the eternal struggle between “good” and “evil”. This may be true of churches, whose hypocrisy is daily exposed in the press, and of simple-minded American presidents – but of historians? Cannadine has chosen to set up a row of straw men rather than engage with what most of his historical colleagues are really up to.

What is most worrying about Cannadine’s argument is the idea that somehow historians have helped to construct a false version of reality. It is simply not the case that for most of human history social groups, peoples, empires and genders have got on reasonably well. Historians reflect in what they write an inherited reality, however distorted or opaque their portrayal of it can sometimes be. It would be absurd to suggest that women have not been – and continue to be – the objects of discrimination, violent coercion and rape, especially where religious institutions or political structures dictate their absolute inferiority. That women’s voices were seldom heard in the distant past or that evidence seems to show they colluded in their own subjection does not diminish the historical reality of male power.

The same objections apply to Cannadine’s smug dismissal of Marxism. Although some workers felt that they were more Catholic than proletarian, or more patriotic than international, or more white than workingclass, industrial capitalism was responsible for the emergence in the 19th century of jerry-built, grimy cities, inhabited by impoverished populations with few amenities, chronic diseases and negligible welfare. Historians have not made up the antagonism between capital and labour, which is rooted in harsh social realities.

Boring though histories of trade unionism might be, they are monuments to the efforts made by ordinary people to better their bargaining power and challenge an industrial elite that realised only very late that treating workers better improved productivity and expanded demand. Political agitators, economists and philanthropists certainly contributed to the process of ameliorating poverty and social disadvantage; historians have only described that process. Rather than create artificial divisions, most historians are at pains to explain how they came about and what their consequences have been.

It is difficult to see what Cannadine wants his profession to do now. He calls on academic historians to abandon the artificial divisions of “identity” history and to celebrate a common humanity “that still binds us together today”. This is 1960s-style cant, a western delusion that bears no resemblance to the realities of either the recent or more distant past. Most of those who live outside the privileged and secure west think not about a common humanity but about the conditions of merely surviving in a world that more closely resembles Darwin’s than it does John Locke’s.

There remain profound differences in the world that have deep historical roots; indeed, it is precisely western hubris that has assumed that if only the Taliban were like us, we would not have to defend “our way of life” in Helmand Province. There is a common humanity only in the most banal sense that we all eat, sleep, have sex and die – as do rabbits and gorillas. The historian’s role is surely to be able to understand those differences and what they signify and to encourage politicians and generals to respect and comprehend difference. No doubt many historians hope that what they write about will also pose a moral challenge to the many surviving forms of discrimination and violence in the world. But ultimately, human life is, as Schopenhauer insisted, a story of “struggle”. Appeals to a common humanity are not going to change that.

Reading Cannadine’s book, I was reminded of John Lennon’s song “Imagine”, written more than 40 years ago: “You may say I’m a dreamer/But I’m not the only one./I hope some day you’ll join us/And the world will be as one.” Keep on imagining.

Richard Overy is professor of history at the University of Exeter. His next book, “The Bombing War: Europe 1939-45”, will be published later this year by Allen Lane